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ID 46924
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Author
Kawakami, Keisuke
Umena, Yasufumi
Kamiya, Nobuo
Abstract
The catalytic center for photosynthetic water-splitting consists of 4 Mn atoms and 1 Ca atom and is located near the lumenal surface of photosystem II. So far the structure of the Mn(4)Ca-cluster has been studied by a variety of techniques including X-ray spectroscopy and diffraction, and various structural models have been proposed. However, its exact structure is still unknown due to the limited resolution of crystal structures of PSII achieved so far, as well as possible radiation damages that might have occurred. Very recently, we have succeeded in solving the structure of photosystem II at 1.9 angstrom. which yielded a detailed picture of the Mn(4)CaO(5)-cluster for the first time. In the high resolution structure, the Mn(4)CaO(5)-cluster is arranged in a distorted chair form, with a cubane-like structure formed by 3 Mn and 1 Ca, 4 oxygen atoms as the distorted base of the chair, and 1 Mn and 1 oxygen atom outside of the cubane as the back of the chair. In addition, four water molecules were associated with the cluster, among which, two are associated with the terminal Mn atom and two are associated with the Ca atom. Some of these water molecules may therefore serve as the substrates for water-splitting. The high resolution structure of the catalytic center provided a solid basis for elucidation of the mechanism of photosynthetic water splitting. We review here the structural features of the Mn(4)CaO(5)-cluster analyzed at 1.9 angstrom resolution, and compare them with the structures reported previously.
Keywords
Crystal structure
Membrane protein structure
Oxygen-evolving complex
Photosystem II
Water-oxidation
Published Date
2011
Publication Title
Journal of Photochemistry and Photobiology B: Biology
Volume
volume104
Issue
issue1-2
Publisher
Elsevier Science SA.
Start Page
9
End Page
18
ISSN
1011-1344
NCID
AA10686173
Content Type
Journal Article
Project
Research Center of New Functional Materials for Energy Production, Storage, and Transport
language
英語
OAI-PMH Set
岡山大学
Copyright Holders
© 2011 Elsevier B.V. All rights reserved.
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True
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